Microanatomical changes of intracerebral arteries in spontaneously hypertensive rats: a model of cerebrovascular disease of the elderly.

Changes occurring in intracerebral arteries of 24-week-old spontaneously hypertensive rats (SHR) compared with age-matched normotensive Wistar-Kyoto (WKY) rats were assessed using microanatomical techniques associated with image analysis. Morphometric parameters investigated included arterial diameter, lumen area, wall area, and wall-to-lumen ratio. Intracerebral arteries (lumen diameter>46 microm) and arterioles (lumen diameter 46-10 microm) of frontal cortex, striatum, and hippocampus were examined. In frontal cortex of SHR arterial wall hypertrophy and luminal narrowing were observed. In striatum, an increase of wall area not accompanied by luminal narrowing predominates resulting in arterial hypertrophy without vasoconstriction. In hippocampal arteries of SHR, luminal narrowing, without changes of wall area was found indicating the occurrence of remodeling. In brain areas investigated, hypertensive changes affected primarily arterioles. The demonstration of a sensitivity of intracerebral arteries to hypertension suggests that changes of these vessels may represent a cause of brain structural alterations occurring in hypertension. The specificity of alterations occurring in intracerebral arteries of brain areas investigated may account for the different localization of cerebral lesions in cerebrovascular disease. The possibility that microanatomical changes developed in intracerebral arteries of SHR may represent a model of cerebrovascular disease of the elderly is discussed.

Changes of retinal neurons and glial fibrillary acid protein immunoreactive astrocytes in spontaneously hypertensive rats.

OBJECTIVE: The influence of arterial hypertension on retinal neurons and glial fibrillary acid protein (GFAP) immunoreactive astrocytes was investigated in spontaneously hypertensive rats (SHRs). METHODS: The retinas of 4- and 6-month-old SHRs and age-matched Wistar-Kyoto rats (WKY) were investigated. A group of SHRs, treated from 4 to 6 months with the hypotensive drug hydralazine, was also examined. Microanatomical and immunohistochemical techniques associated with image analysis and the terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labelling (TUNEL) technique for apoptosis or necrosis were used, as well as astrocyte molecular biology (Western blot) techniques. RESULTS: In 4-month-old SHR and WKY rats, retinal morphology and the number of retinal neurons and of GFAP-immunoreactive astrocytes were similar, with the exception of the occurrence of 1% of TUNEL-positive ganglionic neurons in SHRs. In 6-month-old SHRs a decrease of retinal volume and of the number of ganglionic neurons and photoreceptors was observed, compared with age-matched normotensive WKY rats or younger SHR and WKY rats. Two per cent of ganglionic neurons and 5% of photoreceptors were also TUNEL positive. In 6-month-old SHRs, hypertrophic perivascular GFAP-immunoreactive astrocytes were found, whereas their number was unchanged compared to younger cohorts or WKY rats. An increased expression of GFAP was also noticeable in SHRs by Western blot analysis. Hypotensive treatment with hydralazine partly countered retinal changes occurring in SHRs. CONCLUSIONS: The occurrence of neuronal and astroglial changes when a stable hypertension was developed, and their sensitivity to antihypertensive treatment, suggest that they may represent a hypertension-related phenomenon.

The hippocampus in spontaneously hypertensive rats: a quantitative microanatomical study.

The influence of hypertension on the morphology of hippocampus was assessed in spontaneously hypertensive rats of two, four and six months and in age-matched normotensive Wistar-Kyoto rats. Values of systolic pressure were slightly increased in two-month-old spontaneously hypertensive rats in comparison with age-matched Wistar-Kyoto rats and augmented progressively with age in spontaneously hypertensive rats. No microanatomical changes were observed in the hippocampus of spontaneously hypertensive rats of two months in comparison with age-matched Wistar-Kyoto rats, whereas a decrease of white matter volume was observed in the CA(1) subfield and in the dentate gyrus of four-month-old spontaneously hypertensive rats. In the hippocampus of six-month-old spontaneously hypertensive rats a reduction of grey matter volume both in the CA(1) subfield and in the dentate gyrus, a loss of neurons affecting to a greater extent the CA(1) subfield and an increase of glial fibrillary acid protein-immunoreactive astrocytes was found. The occurrence of apoptosis and/or necrosis identified using the terminal deoxyribonucleotidyl transferase-mediated biotin-16-dUTP nick end labelling technique was also observed in the CA(1) subfield and to a lesser extent in the dentate gyrus. The only change noticeable in the CA(3) subfield of six-month-old spontaneously hypertensive rats was a slight increase in the number of glial fibrillary acid protein-immunoreactive astrocytes. These findings indicate the occurrence of neuronal loss and of astrocyte changes in the hippocampus of spontaneously hypertensive rats of six months, being the CA(1) subfield the area most affected. The relevance of these neurodegenerative changes in hypertension and the possible occurrence of apoptosis and/or necrosis as expression of hypertensive brain damage is discussed.

Autoradiographic localisation of muscarinic cholinergic receptor subtypes in human placenta.

The localisation of M1-M4 muscarinic cholinergic receptor subtypes was investigated in sections of normal human term placenta by light microscope autoradiography. Muscarinic cholinergic receptor subtypes were found almost exclusively in syncytiotrophoblast. Neither other cellular components of placenta, nor blood vessels were labelled. Quantitative analysis of the density of silver grains developed in sections incubated with the different protocols for labelling M1-M4 receptor subtypes, revealed that syncytiotrophoblast expresses all subtypes of muscarinic cholinergic receptor investigated. A higher density of binding sites was found in the apical than in the basal portion of syncytiotrophoblast. The demonstration of muscarinic cholinergic receptors in syncytiotrophoblast suggests that a cholinergic system may have a role in regulating transport of compounds from maternal to foetal interface.

Forebrain white matter in spontaneously hypertensive rats: a quantitative image analysis study.

The volume and the morphology of brain white matter as well as the number and the size of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes were investigated in 6-month-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats. The volume of frontal and occipital cortex and of hippocampus was decreased in SHR in comparison with normotensive rats, whereas the volume of neostriatum was unchanged. A remarkable decrease of the volume of internal capsule and striosomes, a moderate reduction of that of corpus callosum and no changes of the volume of external capsule and of white matter of hippocampus were also observed in SHR. In SHR the number of astrocytes was higher in the frontal and occipital cortex and in the white matter of the CA1 and CA3 subfields of the hippocampus, but not in the corpus callosum or in the grey matter of the CA1 and CA3 subfields. Staining for myelin did not reveal alterations in single fibre sheath morphology. These findings indicate the occurrence of changes of forebrain white matter in SHR, consisting in the reduction of it without qualitative modifications of myelinated fibres. The development of gliosis apparently not related with changes of volume of white matter was also found.

Sulfatides and arylsulfatase A activity in major salivary glands of hamster (Mesocricetus auratus) after adenocarcinoma induction in oral cavity.

A biochemical study of sulfatides and arylsulfatase A (ASA) was carried out in the submandibular and sublingual glands of the male and female hamster Mesocricetus auratus after experimental induction of oral adenocarcinoma by 7,12-dimethylbenzanthracene (DMBA). Hamster experimental groups included control animals, animals treated with beta-carotene, animals treated with DMBA, and animals treated with DMBA plus beta-carotene. Oral cavity treatment with DMBA induced carcinogenesis in the buccal mucosa, but not in the major salivary glands, where nevertheless, the morphology and expression of both parameters examined changed. In fact, sulfatide concentrations and enzyme activity increased significantly, while in control and beta-carotene-treated hamsters they were similar in both glands and sexes. After administration of DMBA plus beta-carotene, sulfatide concentration decreased, as did ASA activity, slightly in the submandibular gland and remarkably so in the sublingual one of female hamsters. Thin-layer chromatography (TLC) analysis of lipid patterns, after DMBA treatment, revealed considerable differences, not only in sulfatides, but also in other lipid fractions, as well as between the two glands and two sexes. These findings show that oral cavity treatment with DMBA is not able to induce carcinogenesis in the major salivary glands examined; however, it does cause considerable metabolic changes.

Expression of acidic glycosphingolipids and arylsulphatase A activity in human pathological endometrium.

Endometrium biopsic samples from women with cystic hyperplasia or adenocarcinoma were analysed by biochemical procedures to verify fluctuations in the acidic glycosphingolipid (sulphatide) concentration and arylsulphatase A (ASA) activity. Comparing the values of the considered parameters with those obtained in normal subjects, it was observed that ASA activity significantly increased in both pathologies; in contrast, sulphatide concentration underwent a non-significant decrease in hyperplasia and a statistically significant increase in neoplasia. The thin-layer chromatography (TLC) images revealed not only quantitative, but also qualitative differences in the lipid fractions. In fact, compared with controls, the sulphatides showed one more marked fraction in the neoplastic endometrium, and two fractions with different Rf values in the hyperplastic one. Moreover, two new unknown fractions also appeared in some subjects with cystic hyperplasia. The findings suggest the lipid metabolism undergoes considerable changes under the pathological conditions examined. The fluctuations observed, in particular, in the sulphatide concentration are believed to be related to changes in the biosynthetic and catabolic activities of the key enzymes directly involved in their metabolism, i.e. arylsulphatase A and sulphotransferase, which are regulated by sex hormones.

Arylsulphatases A and B in the oviduct of female rabbits in anestrus and estrus conditions.

An investigation has been carried out on the activity of arylsulphatases A and B (ASA and ASB) in the oviduct of rabbits in anestrus and estrus conditions. The histochemical and biochemical results obtained have demonstrated that both arylsulphatases are present in the ampulla tract and in the isthmic one, and that the estrus determines a considerable increase in the specific activity of ASB. Hypothesis are advanced on the probable-meaning of the variations in the activity of these enzymes, particularly in relation to the secretion of glycoconjugates by the epithelium of the oviduct.

Ultrastructural histochemical study on glycoconjugates of the submandibular gland of rabbits.

An ultrastructural histochemical study was carried out on submandibular glands of rabbits. Stainings were performed with dialysed iron (DI), high iron diamine (HID), tannic acid uranyl acetate (TA-U), tannic acid-ferric chloride (TA-F) sequence, and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method. It was demonstrated that neutral glycoproteins are present in the cells with dark granules of the preterminal tracts, and that neutral and acid glycoproteins are present in the cells with light granules of the terminal tracts. Result are discussed and compared to other previously obtained histochemical and biochemical data.

Soluble arylsulphatases in the rabbit salivary glands. A light and electron microscopy study.

A histochemical study was effected, by light and electron microscopy, on the activity of arylsulphatases A and B in the submandibular and sublingual glands of male and female rabbits, distinguishing, among the latter, between the physiological estrus and anestrus condition. The results obtained demonstrated that the enzymatic activity is more intense in the sublingual gland and that the estrus condition causes an increase in this activity. No correlation was found between the topochemical distribution of the soluble arylsulphatases and that of sulphates.

Localization of the activity of arylsulphatases A and B in the rat salivary glands.

A histochemical study has been carried out by light and electron microscopy on the localization of the activity of arylsulphatases A and B in the salivary glands of rat. Results obtained indicate that in the submandibular gland a greater activity is present in the cells of the convoluted granular tubules than in the acina cells, whereas in the sublingual gland the cells of the preterminal tracts appear to be more reactive than those of the terminal tracts. The probable role played by these sulphatases is discussed.

A rapid procedure for elimination of non-polar lipids hampering the usual polar lipid extraction and TLC separation.

A new and rapid method is proposed for extraction of non-polar lipids from tissues where they are present as abundant components which can interfere with the usual procedures of lipid extraction and TLC separation, and hamper, in particular, sulphatide visualization. A solvent more hydrophobic than chloroform, i.e. n-hexane, was utilized to remove the neutral lipids from samples of female rabbit parotid gland, and the n-hexane phase was used for TLC which showed considerable amounts of cholesterol esters, in addition to triglycerides, diglycerides and monoglycerides. The methanol phase, now devoid of non-polar lipids, was utilized to prepare TLC plates in order to separate and visualize the polar lipid fractions, in particular the sulphatides.

Fluctuations in levels of various gangliosides in the different tracts of the oviduct of the frog (Rana esculenta) during the reproductive cycle.

The ganglioside content and pattern have been followed in the different tracts (rectus, convoluted and uterine) of the frog oviduct during the reproductive cycle. The main variations we observed are: a) average higher levels of ganglioside sialic acid in the preovulatory phase, with two peaks in March and April for the convoluted and rectus tract, respectively, and a more homogenous behaviour for the uterine tract; in all three tracts of the oviduct a minimum coincident with the ovulation has been found; b) a balanced presence of sulfolipids and gangliosides in the uterine tract: in fact sulfolipids, whose variations have been determined in a previous work, are higher when gangliosides are lower and vice versa, maintaining nearly constant the total negative charge due to these glycolipids; c) an alternate fluctuation of monosialo- and disialo-gangliosides in the preovulatory phase and a net trend toward the increase of monosialo- and the decrease of disialogangliosides in the postovulatory phase; trisialo-gangliosides are in general less represented and show less marked variations; d) the presence of particular gangliosides in particular moments of the reproductive cycle: Fuc-GM1, a fucosylated ganglioside, is higher than the more represented GM1 during the ovulation, while GD1 alpha, a ganglioside with a sialic acid residue linked to GalNAc, is steadily present in all three tracts after ovulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arylsulphatase activity in the oviduct of the frog Rana esculenta. I. Oestradiol-induced changes following ovariectomy and hypophysectomy.

The effects of oestradiol treatment on arylsulphatase activity in the frog oviduct are reported. Oestradiol-induced changes were also investigated in ovariectomized and hypophysectomized animals. Under all the experimental conditions, hormonal treatment causes an increase in enzyme activity. This can be observed biochemically and also histochemically on frozen sections. Hypotheses are advanced to explain fluctuations in arylsulphatase activity.

[Further comparative anatomical observations on some histochemical aspects of the salivary glands of rodents in the course of development. II]. / Ulteriori osservazioni anatomo comparate su alcuni aspetti istochimici delle ghiandole salivari dei roditori nel corso dello sviluppo. II

The PAS and protein reaction positive secretion can be found in the parotid and inframandibular gland of rabbit on the 22nd pregnancy day only in the perinuclear zone. On the contrary during the last developmental phase it is localized in the apical zone of the cells and after the birth in all the cytoplasm with the exception of the terminal tracts of the inframandibular gland, which are always PAS negative but positive to the reaction to MPS sulfurated acids. Assumptions are made about the presence of the secretion in the gland cells during the fetal period.

Arylsulphatase A activity and sulphatide concentration in the female rabbit oviduct are under physiological hormonal influence.

Oviduct samples of female rabbits in different phases of the reproductive cycle were analysed to establish the role of sex steroid hormones in the regulation of sulphatide concentration and arylsulphatase A activity. In addition to biochemical procedures, histochemical techniques were used to localize both enzyme activity and the natural substrate. The plasma concentrations of progesterone and 17 beta-oestradiol were determined by radioimmunoassay (RIA). The findings show that the parameters examined undergo considerable changes during the different phases of the reproductive cycle. Oestrogens exert an inducing action on arylsulphatase A activity, while progesterone inhibits it. Fluctuations of the catabolic arylsulphatase activity condition the sulphatide concentration, which reaches maximum values at the eighth post-ovulatory day when progesterone dominance is consolidated. In this phase of the reproductive cycle, thin-layer chromatography confirms the presence not only of larger quantities of sulphatides, but also of all other lipid fractions.